This section provides background information related to the present disclosure and is not necessarily prior art.
Emission regulation requirements are mandating that engines have exhaust aftertreatment systems to eliminate, or at least substantially minimize, the emission of, for example, particulate matter and NOX. To eliminate or reduce the emission of particulate matter and NOX, exhaust after-treatment systems can include components such as a particulate filter (e.g., a diesel particulate filter (DPF)), a selective catalyst reduction (SCR) component, and a diesel oxidation catalyst (DOC) component.
SCR and DOC components generally work in conjunction with fluid delivery systems that inject a fluid (e.g., a hydrocarbon fluid, urea or other reagent) into the exhaust stream to treat the exhaust before the exhaust enters the SCR or DOC components. In the case of SCR, a reductant solution including urea, for example, may injected into the exhaust stream before entry into the SCR component. In the case of DOC, a hydrocarbon reductant such as diesel fuel is injected into the exhaust stream before entry into the DOC component.
The fluid delivery systems involve the integration of injectors, pumps, filters, valves, and other necessary control devices to control the dosing of each of these fluids into the exhaust stream. In general, fluid delivery systems for light, medium, and heavy-duty trucks, for example, may include a single injection source for dosing the fluid into the exhaust stream. Fluid delivery systems for large-scale engines for locomotive, marine, and stationary applications may include multiple injection sources for injecting the fluid into the exhaust stream. These large-scale applications, therefore, can be difficult to design to overcome various issues such as maintaining proper injector pressure, system durability, sufficient reductions of harmful emission (e.g., particulate matter and NOX), cost, and maintenance. The principles of the present disclosure provide for more precise control of fluid pressure at the injectors so that the spray droplet size of the fluid can be more precisely regulated within a tighter tolerance.